What unexpected incident kept Buck and Spitz from finishing their first fight in "Call of the Wild"?

While Buck and Spitz are fighting, the camp is suddenly overrun by a pack of "starving huskies, four or five score of them, who had scented the camp from some Indian village".  Mad with hunger, the huskies steal all the grub they can find, and when they are confronted by "the astonished team-dogs", set upon them with a vengeance.  There is no opposing the skeletal scavengers, who, "with blazing eyes and slavered fangs", attack with terrifying and desperate intensity.  Buck must fight for his life, and at the same time, fend off treacherous attacks by Spitz, who, despite the chaos, still singlemindedly pursues their battle for ascendancy.  Battered and bleeding, the team-dogs eventually flee, and gather together later in the shelter of the forest.  The personal rivalry between Buck and Spitz is finally put aside for the present, and at daybreak, the team "limp(s) warily back to camp to find the mauraders gone" (Chapter 3).